The 15th bi-annual Gordon Research Conference (GRC) on Phagocytes will be held June 7-12, 2009 at Waterville Valley Resort, Waterville Valley, NH. This Conference will be a forum for high-quality presentations and in depth discussions of the most recent discoveries in phagocyte biology and clinical extensions relevant to inflammation and host defense. The Conference has been in existence since 1981, and draws from a world-wide group of scientists with diverse backgrounds, including cell biology, biochemistry, molecular genetics, and clinical medicine. This meeting has consistently been an important venue for disseminating information and facilitating communication between investigators studying different facets of leukocyte biology as well as providing a general educational forum for trainees and young investigators in the field. Conferees attending the Gordon Research Conference on Phagocytes (session chairs, speakers, and participants) typically number 130-140. At the 2007 meeting, approximately 2/3 of conferees were faculty-level research scientists and 1/3 were graduate students and postdoctoral fellows. There are nine planned sessions with a total of 30 plenary talks. A known expert in the field will chair each session. We also plan to include approximately 6-8 short talk presentations selected from abstracts submitted by meeting attendees. In addition, we anticipate that at least 70 posters will be displayed. The program will provide opportunities for participation of scientists at all levels and we will particularly promote the participation of junior investigators, postdoctoral trainees and "new investigators to the field". For the first time, the 2009 Conference will incorporate a Graduate Research Seminar (GRS) on June 6-7, 2009 just prior to the start of the GRC. The GRS will provide an informal venue for graduate students and postdoctoral fellows to present their research in a peer environment. Speakers (approximately 12) for two science sessions will be chosen from submitted abstracts and we anticipate 35-40 attendees. All conferees will present posters and are expected to attend the subsequent GRC. We believe that the informal interaction and opportunity to present their data will be invaluable experiences for young researchers.